CVE-2026-18208: Red Hat Build Of Keycloak

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

A flaw was found in the OIDC token introspection endpoint of the keycloak-services component. Keycloak is an open-source identity and access management solution used to secure modern applications and services. The issue occurs when a confidential client, configured to receive signed JWT introspection responses, attempts to introspect a token issued for a different audience. Although the endpoint correctly identifies the token as inactive for that client, it still returns the full set of token claims within a signed JWT field. This allows an unauthorized client to bypass audience-based restrictions and access sensitive information contained in the token.

Affected products

• Red Hat Build Of Keycloak: affected versions not specified

Published 2026-07-31. Last modified 2026-08-07.